A large number of wells have been drilled into earth strata for the extraction of oil, gas, and other material therefrom. In many cases, such wells are found to be initially unproductive, or decrease in productivity over time, even though it is believed that the surrounding strata still contains extractable oil, gas or other material. Such wells are typically vertically extending holes including a casing usually of mild steel pipe having an inner diameter of from just a few inches to about eight (8) inches in diameter for the transportation of the oil, gas or other material upwardly to the earth's surface.
In an attempt to obtain production from unproductive wells and increase production in under producing wells, methods and apparatus for cutting a hole in the well casing and forming a lateral passage therefrom into the surrounding earth strata are known. Reference for instance, Landers U.S. Pat. No. 5,413,184 issued May 9, 1995; and Schellsteed U.S. Pat. No. 4,640,362 issued Feb. 3, 1987, which disclose exemplary methods and apparatus for producing lateral holes in the earth's strata surrounding a well casing. However, such known methods and apparatus have not yet been known to provide satisfactory results. In particular, the known apparatus of Landers utilizes a non-rotating blasting type fluid nozzle wherein fluid under pressure is directed at the earth's strata has been found to be unable to produce a hole in the strata of more than a few inches in depth. This shortcoming is believed to be due largely to the inability of the non-rotating blaster type nozzles to form a passage in the strata sufficiently unobstructed to allow advancement of the nozzle into the strata, particularly in strata having suitable porosity and permeability characteristics for oil, gas and/or other commercial products. Also, it has been found that any formation that a well is located in will produce a given hydrostatic head in the well which is equal to the formation pressure. This is problematic because the formation has a capability of absorbing fluid around the nozzle, including immediately ahead of and shortly behind the nozzle, when the hydrostatic head becomes greater than the formation pressure, resulting in at least partial and in many cases total stoppage of movement of cuttings away from the nozzle.
Accordingly, the present invention is directed to overcoming one or more of the problems as set forth above.